Transcript for Letter with powder sent to Trump Jr.'s apartment: Police

There are also new details about that trump family scare, a white powder sending don junior's wife Vanessa to the hospital. The president's daughter-in-law is speaking out after handling that suspicious envelope and we've learned what exactly that white powder was. This morning, the president's son don junior and his wife Vanessa recovering from a scare. Someone sending a suspicious envelope to their New York City apartment postmarked from Boston. It was addressed to don junior but Vanessa trump opening the letter to find a white powder inside. She called 911 just after 10:00 A.M. Monday telling police she felt dizzy. Respond to 44th suspicious substance. Reporter: Firefighters treating her and two others at the apartment. Then taking them to this hospital in Manhattan for evaluation and precautionary tests. The powder later deemed to be N nonhazardous and sources telling ABC news it was just cornstarch but the threat prompting the white house to react. I know the president spoke with her. Beyond that at this point it's an ongoing and active investigation so I can't comment any further. Reporter: Sources tell ABC news that letter expressed anger towards don junior but not the president. Earlier don junior tweeting thankful that Vanessa and my children are safe and unharmed after the incredibly scary situation that occurred this morning. Truly disgusting that certain individuals choose to express their opposing views with such disturbing behavior. And thanking the secret service and NYPD for their decisive action and support to his family in making a rough day manageable. Now, Vanessa trump sent out this tweet thank you so much for all the help today in New York City, appreciate all the quick response to make sure that I was safe. She also thanked all those responding agencies as well including the FBI and the secret service, guys. Glad it worked out. Thanks, Tom.

This transcript has been automatically generated and may not be 100% accurate.

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